The present invention relates to crosslinked phenoxyphosphazene compounds, flame retardants, flame-retardant resin compositions and moldings of flame-retardant resins.
Plastics are used for applications such as electric and electronic products, office automation equipment, office equipment and communications equipment because of their excellent processability, mechanical properties, appearance and the like. The resins used in these applications are required to have flame retardancy for protection against the heat and ignition of internal parts in devices and appliances.
In order to impart flame retardancy to thermoplastic resins or thermosetting resins, a flame retardant is generally added to the resin prior to molding of the resin. Known as flame retardants are inorganic hydroxides, organic phosphorus compounds, organic halogen compounds, halogen-containing organic phosphorus compounds and the like.
Among said flame retardants, those having high flame-retardancy are halogen-containing compounds such as organic halogen compounds, halogen-containing organic phosphorus compounds and the like.
However, these halogen-containing compounds undergo thermal decomposition during molding of the resin to generate hydrogen halide, thereby causing corrosion of the metallic mold and degradation and discoloration of the resin. Another problem is that, when the resin is burned in a fire or the like, hydrogen halide and the like are evolved as gases and smokes detrimental to organisms.
On the other hand, halogen-free flame retardants are magnesium hydroxide, aluminum hydroxide and like inorganic hydroxides and organic phosphorus compounds.
However, the inorganic hydroxides exhibit flame retardancy due to water generated by thermal decomposition, and therefore produce only low flame-retardancy. Consequently, the inorganic hydroxide must be added in a large amount, but such a large amount addition entails a disadvantage that the inherent properties of resins are impaired.
The organic phosphorus compounds are widely. used because they give relatively high flame-retardancy. Known as typical organic phosphorus compounds are triphenyl phosphate (TPP), tricresyl phosphate (TCP) and the like. However, these organic phosphorus compounds are liquid or low melting solid and thus have a high volatility, posing problems such as lowering of the molding temperature of resins, blocking and their migration to the surface (juicing) during kneading.
Furthermore, resin compositions containing said organic phosphorus compound have the drawback of dripping (falling of molten resin droplets) during burning and spreading of a fire due to the dripping. Consequently, in order to obtain a rating of V-0 (flaming does not continue for more than a specified period, and there are no molten resin drips which ignite cotton) in a flame retardancy test UL-94 (Testing for Flammability of Plastic Materials for Parts in Devices and Appliances) which is a standard test for evaluating flame retardancy, by adding an organic phosphorus compound to a resin, it is necessary to add a fluorine-containing resin such as polytetrafluoroethylene (PTFE) as an agent for preventing dripping of molten resin during burning. However, the fluorine-containing resin contains halogen and evolves gases harmful to human body during combustion, as stated above.
In view of the foregoing prior art drawbacks, it is desired to develop a novel flame retardant which is free of halogen, which has a high melting point and a low volatility, which would not impair the inherent properties of resins such as mechanical properties and processability, which is free from the problems of inducing blocking and juicing during kneading and which does not permit dripping during flaming.
An object of the present invention is to provide a compound useful as a flame retardant.
Another object of the invention is to provide a halogen-free flame retardant.
A further object of the invention is to provide a flame retardant which has a high melting point and a low volatility and which does not impair the inherent properties of resins, such as mechanical properties and processability.
A still further object of the invention is to provide a flame retardant which does not present the problems of blocking and juicing in kneading.
Another object of the invention is to provide a flame retardant which does not induce dripping during burning.
An additional object of the invention is to provide a flame retardant which is free from the prior art problems.
A still further object of the invention is to provide a flame-retardant resin composition containing the foregoing flame retardant.
Another object of the invention is to provide a molded articles of flame-retardant resin produced by molding said flame-retardant resin composition.
Another object of the invention is to provide a method for imparting flame retardancy to molded articles of resins.
An additional object of the invention is to provide use of a phosphazene compound for imparting flame retardancy to resin molded articles.
Other features of the present invention will become apparent from the following description.
The inventors of the present invention conducted extensive research to overcome the foregoing prior art problems and found that certain partly crosslinked phenoxyphosphazene compounds can be the desired flame retardants. The present invention was completed based on this novel finding.
According to the present invention, there is provided a crosslinked phenoxyphosphazene compound characterized in that at least one phosphazene compound selected from the group consisting of a cyclic phosphazene compound represented by the formula (1) 
wherein m is an integer of 3 to 25 and Ph is phenyl group and a straight-chain phosphazene compound represented by the formula (2) 
wherein X represents a group xe2x80x94Nxe2x95x90P(OPh)3 or a group xe2x80x94Nxe2x95x90P(O)OPh, Y represents a group xe2x80x94P(OPh)4 or a group xe2x80x94P(O)(OPh)2, and n is an integer of 3 to 1000, and Ph is as defined above is crosslinked with at least one crosslinking group selected from the group consisting of o-phenylene group, m-phenylene group, p-phenylene group, biphenylene group, and a group 
wherein A is xe2x80x94C(CH3)2xe2x80x94, xe2x80x94SO2xe2x80x94, xe2x80x94Sxe2x80x94 or xe2x80x94Oxe2x80x94; wherein each of said crosslinking groups is interposed between the two oxygen atoms left after the elimination of phenyl groups from the phosphazene compound; and wherein the amount of the phenyl groups in the crosslinked compound is 50 to 99.9% based on the total amount of the phenyl groups in said phosphazene compound represented by the formula (1) and/or said phosphazene compound represented by the formula (2).
According to the present invention, there is also provided a flame retardant comprising said crosslinked phenoxyphosphazene compound (this flame retardant will hereinafter be referred to as xe2x80x9cflame retardant Axe2x80x9d).
Flame retardant A comprising the crosslinked phenoxyphosphazene compound of the present invention does not contain halogen, and therefore does not cause the corrosion of the mold and degradation and discoloration of the resin due to the generation of hydrogen halide by thermal decomposition during the resin molding operation, and does not produce gases and smokes detrimental to organisms, such as hydrogen halide, when the resin is burned in a fire or the like. Further, the crosslinked phenoxyphosphazene compound of the present invention has a low volatility and does not lower the molding temperature, and is free from the shortcomings such as blocking or their migration to the surface (juicing) during kneading, and dripping during burning. The incorporation of flame retardant A does not impair inherent properties of resins, such as impact resistance and like mechanical properties, heat resistance, processability and the like.
According to the present invention, there are also provided: (a) a flame-retardant resin composition comprising 100 parts by weight of a thermoplastic resin or a thermosetting resin and 0.1 to 100 parts by weight of flame retardant A; (b) a flame-retardant resin composition comprising 100 parts by weight of a thermoplastic resin or a thermosetting resin, 0.1 to 100 parts by weight of flame retardant A and 0.01 to 50 parts by weight of an inorganic filler; (c) a flame-retardant resin composition comprising 100 parts by weight of a thermoplastic resin or a thermosetting resin, 0.1 to 50 parts by weight of flame retardant A and 0.1 to 50 parts by weight of an organic phosphorus compound free of halogen; and (d) a flame-retardant resin composition comprising 100 parts by weight of a thermoplastic resin, 0.1 to 100 parts by weight of flame retardant A and 0.01 to 2.5 parts by weight of a fluorine-containing resin.
According to the present invention, there are provided flame-retardant resin molded articles produced by molding any of flame-retardant resin compositions (a) to (d).
Furthermore, the inventors of the present invention found that the foregoing contemplated effects of the invention can be achieved likewise when using at least one phosphazene compound selected from the group consisting of the cyclic phosphazene compound represented by the formula (1) and the straight-chain phosphazene compound represented by the formula (2) in combination with an inorganic filler or an organic phosphorus compound free of halogen.
According to the present invention, there is provided a flame retardant comprising at least one phosphazene compound selected from the group consisting of the cyclic phosphazene compound represented by the formula (1) and the straight-chain phosphazene compound represented by the formula (2) (said flame retardant will hereinafter be referred to as xe2x80x9cflame retardant Bxe2x80x9d).
According to the present invention, there are also provided: (e) a flame-retardant resin composition comprising 100 parts by weight of a thermoplastic resin or a thermosetting resin, 0.1 to 100 parts by weight of flame retardant B and 0.01 to 50 parts by weight of an inorganic filler; and (f) a flame-retardant resin composition comprising 100 parts by weight of a thermoplastic resin or a thermosetting resin, 0.1 to 50 parts by weight of flame retardant B, and 0.1 to 50 parts by weight of an organic phosphorus compound free of halogen.
According to the present invention, there are provided flame-retardant resin molded articles produced by molding any of flame-retardant resin compositions (e) and (f).
The inventors of the present invention also found that the foregoing contemplated effects of the invention can be achieved when using, as a flame retardant, at least one phosphazene compound selected from the group consisting of a cyclic phosphazene compound represented by the formula (3) and a straight-chain phosphazene compound represented by the formula (4).
According to the present invention, there is provided a flame retardant comprising at least one phosphazene compound selected from the group consisting of a cyclic phosphazene compound represented by the formula (3). 
wherein m is as defined above, R1 is a cyano-substituted phenyl group, R2 represents an alkyl group having 1 to 18 carbon atoms, a group 
or a group 
wherein R3 is a hydrogen atom, cyano group, alkyl group having 1 to 10 carbon atoms, allyl group or phenyl group; when two or more R2 groups exist, the R2 groups may be the same or different; p and q are numbers which fulfil the requirements that p greater than 0, qxe2x89xa70, and p+q=2, and a straight-chain phosphazene compound represented by the formula (4) 
wherein n, R1, R2, p and q are as defined above, Xxe2x80x2 represents a group xe2x80x94P(OR1)4, a group xe2x80x94P(OR1)3(OR2), a group xe2x80x94P(OR1)2(OR2)2, a group xe2x80x94P(OR1)(OR2)3, a group xe2x80x94P(OR2)4, a group xe2x80x94P(O)(OR1)2, a group xe2x80x94P(O)(OR1)(OR2), or a group xe2x80x94P(O)(OR2)2, and Yxe2x80x2 represents a group xe2x80x94Nxe2x95x90P(OR1)3, a group xe2x80x94Nxe2x95x90P(OR1)2(OR2), a group xe2x80x94Nxe2x95x90P(OR1)(OR2)2, a group xe2x80x94Nxe2x95x90P(OR2)3, a group xe2x80x94Nxe2x95x90P(O)OR1 or a group xe2x80x94Nxe2x95x90P(O)OR2 (this flame retardant will hereinafter be referred to as xe2x80x9cflame retardant Cxe2x80x9d).
According to the present invention, there is provided a flame-retardant resin composition comprising 100 parts by weight of a thermoplastic resin or a thermosetting resin and 0.1 to 100 parts by weight of flame retardant C.
According to the present invention, there are provided a flame-retardant resin molded article obtainable by molding said flame-retardant resin composition.
According to the present invention, there is also provided a method for imparting flame retardancy to a resin molded article using flame retardant A, flame retardant B or flame retardant C. For example, by incorporating flame retardant A, flame retardant B or flame retardant C to a resin and molding the mixture, there is provided a resin molded article having a flame retardancy imparted.
According to the present invention, there is provided use of the phosphazene compounds for imparting flame retardancy to a resin.
Crosslinked Phenoxyphosphazene Compounds
The phenoxyphosphazene compounds of the invention can be obtained by, for example, reacting dichlorophosphazene oligomers (a mixture of cyclic dichlorophosphazene oligomers and straight-chain dichlorophosphazene oligomers) with an alkali metal salt of phenol and an alkali metal salt of an aromatic dihydroxy compound. Concerning the dichlorophosphazene oligomers, each of the cyclic and straight-chain dichlorophosphazene oligomers may be isolated from the mixture and used singly. The alkali metal salt of the phenol and the alkali metal salt of the aromatic dihydroxy compound may be mixed together before being subjected to the reaction. Alternatively, the alkali metal salt of phenol and the alkali metal salt of the aromatic dihydroxy compound are consecutively subjected to the reaction in this order or in the reverse order.
The dichlorophosphazene oligomer can be produced by known methods disclosed in, for example, Japanese Unexamined Patent Publication No. 87427/1982 and Japanese Examined Patent Publications Nos. 19604/1983, 1363/1986 and 20124/1987. An exemplary method comprises reacting ammonium chloride and phosphorus pentachloride (or ammonium chloride, phosphorus trichloride and chlorine) at about 120 to 130xc2x0 C. using chlorobenzene as a solvent, followed by removal of hydrochloric acid.
Examples of the alkali metal salts of phenol include Na salt, K salt and Li salt of phenol. Examples of the alkali metal salts of aromatic dihydroxy compounds include any of the alkali metal salts of known compounds having one or more benzene rings and two hydroxy groups in the molecule. Examples of such alkali metal salts include alkali metal salts of resorcinol, hydroquinone, catechol, 4,4xe2x80x2-isopropylidene diphenol (bisphenol-A), 4,4xe2x80x2-sulfonyldiphenol (bisphenol-S), 4,4xe2x80x2-thiodiphenol, 4,4xe2x80x2-oxydiphenol and 4,4xe2x80x2-diphenol. The alkali metal salts are not limited, but Li salt is preferred. The alkali metal salts of aromatic dihydroxy compounds may be used either singly or in combination.
The alkali metal salt of phenol and the alkali metal salt of the aromatic dihydroxy compound are used in amounts such that the combined amount of the two alkali metal salts, relative to the dichlorophosphazene oligomers, is usually about 1 to 1.5 equivalents (based on the chlorine content of the dichlorophosphazene oligomers), preferably about 1 to 1.2 equivalents (based on the chlorine content of the dichlorophosphazene oligomers). The ratio of the two alkali metal salts (the alkali metal salt of the aromatic dihydroxy compound/the alkali metal salt of phenol, molar ratio) is not paticularly limited and can be suitably selected from a wide range, but is usually about 1/2000 to 1/4. Using the alkali metal salts in the ratio within the above range, the desired crosslinked phenoxyphsphazene compound of the invention can be obtained.
If the ratio is markedly lower than 1/2000, the resulting crosslinked compound has low effect, and it may become difficult to achieve the above objects, such as prevention of dripping of molten resin. On the other hand, if the ratio is much higher than 1/4, the crosslinking proceeds to an excess degree and may result in a crosslinked phenoxyphosphazene compound which is insoluble and infusible and thus has decreased dispersiblility into resins.
The reaction of the dichlorophosphazene oligomers with said two alkali metal salts is carried out at a temperature between room temperature and about 150xc2x0 C., in a solvent such as an aromatic hydrocarbon (e.g.,toluene) or a halogenated aromatic hydrocarbon (e.g., chlorobenzene).
The terminal groups X and Y in the formula (2) vary in accordance with the reaction conditions and other factors. If the reaction is carried out under ordinary conditions, e.g., under mild conditions in a non-aqueous system, the resulting product will have a structure wherein X is xe2x80x94Nxe2x95x90P(OPh)3 and Y is xe2x80x94P(OPh)4. If the reaction is carried out under such conditions that moisture or an alkali metal hydroxide is present in the reaction system, or under so severe conditions that a rearrangement reaction occurs, the resulting product will have a structure wherein X is xe2x80x94Nxe2x95x90P(OPh)3 and Y is xe2x80x94P(OPh)4 and additionally a structure wherein X is xe2x80x94Nxe2x95x90P(O)OPh and Y is xe2x80x94P(O)(OPh)2.
The crosslinked phenoxyphosphazene compound of the invention is thus obtained. The decomposition temperature of the crosslinked phenoxyphosphazene compound of the invention is usually in the range of 250 to 350xc2x0 C.
In the above process, if the dichlorophosphazene oligomers are reacted only with the alkali metal salt of phenol and is not reacted with the alkali metal salt of the aromatic dihydroxy compound, a cyclic phosphazene compound of the formula (1) or a straight-chain phosphazene compound of the formula (2) is produced. On the other hand, when the alkali metal salt of the aromatic dihydroxy compound is used in addition to the alkali metal salt of phenol, there is provided the crosslinked phenoxyphosphazene compound of the invention, wherein part of the phenyl groups in the cyclic phosphazene compound of the formula (1) and/or the straight-chain phosphazene compound of the formula (2) are substituted by the crosslinking groups.
The proportion of the phenyl groups of the crosslinked phenoxyphosphzene compound of the invention is 50 to 99.9%, preferably 70 to 90%, based on the total amount of the phenyl groups in the phosphazene compound of the formula (1) and/or phosphazene compound of the formula (2).
The crosslinked phenoxyphosphazene compound of the invention is isolated and purified from the reaction mixture by a conventional isolation method such as washing, filtration, drying or the like.
Flame Retardant
(a) Flame retardant A
Flame retardant A comprises the crosslinked phenoxyphosphazene compound of the present invention.
(b) Flame retardant B
Flame retardant B will be described below.
The cyclic phosphazene compounds of the formula (1) and the straight-chain phosphazene compounds of the formula (2) are known compounds. These phosphazene compounds are disclosed in, for example, James E. Mark, Harry R. Allcock, Robert West, xe2x80x9cInorganic Polymersxe2x80x9d Pretice-Hall International, Inc., 1992, pp. 61-140.
The cyclic phosphazene compound of the formula (1) and the straight-chain phosphazene compound of the formula (2) can be produced by, for example, following the above process for producing the crosslinked phenoxyphosphazene compound except that the alkali metal salt of the aromatic dihydroxy compound is not used.
The obtained phosphazene compound is isolated and purified from the reaction mixture by a conventional isolation method such as washing, filtration, drying or the like.
Specific examples of the cyclic phosphazene compounds of the formula (1) include phosphazene compounds in which phenoxy groups are substituted in a mixture of cyclic and straight-chain chlorophosphazenes wherein n is an integer of 3 to 25, e.g., hexachlorocyclotriphosphazene, octachlorocyclotetraphosphazene and the like, prepared by reacting ammonium chloride and phosphorus pentachloride at 120 to 130xc2x0 C.; and hexaphenoxycyclotriphosphazene, octaphenoxycyclotetraphosphazene and decaphenoxycyclopentaphosphazene and like cyclic phosphazene compounds obtained by isolating, from the above mixture of chlorophosphazenes, hexachlorocyclotriphosphazene, octachlorocyclotetraphosphazene, decachlorocylopentaphosphazene or the like, and substituting the isolated product by phenoxy groups.
Specific examples of the straight-chain phosphazene compounds of the formula (2) include those obtained by heating hexachlorocyclotriphosphazene to 220 to 250xc2x0 C. for ring-opening polymerization and substituting, by phenoxy groups, the resulting dichlorophosphazene wherein n is an integer of 3 to 1000.
Among these examples, phosphazene compounds obtained by substituting, by phenoxy groups, a mixture of cyclic or straight-chain chlorophosphazenes wherein n is an integer of 3 to 25.
(c) Flame retardant C
Flame retardant C will be described below.
As the phosphazene compound of the formula (3), preferred are, for example, cyclic phosphazene compounds wherein R1 is a cyano-substituted phenyl group, R2 is an alkyl group having 1 to 8 carbon atoms, a group 
or a group 
and R3 is a hydrogen atom, alkyl group having 1 to 4 carbon atoms or allyl group, p is 0.3 to 1.7, and q is 0.3 to 0.7.
As the phosphazene compounds represented by the formula (4), preferred are, for example, straight-chain phosphazene compounds wherein R1 is a cyano-substituted phenyl group, R2 is an alkyl group having 1 to 8 carbon atoms, a group 
or a group 
R3 is a hydrogen atom, alkyl group having 1 to 4 carbon atoms or allyl group, p is 0.3 to 1.7, and q is 0.3 to 0.7.
The cyano-substituted phenyl group represented by R1 is, for example, 2-cyanophenyl, 3-cyanophenyl or 4-cyanophenyl group, and so on.
More specifically, the phosphazene compounds represented by the formulas (3) and (4) include cyclic phosphazene compounds or straight-chain phosphazene compounds, such as cyclotriphosphazene, cyclotetraphosphazene and cyclopentaphosphazene, each substituted by both cyanophenoxy and phenoxy groups.
Specific examples of cyclic phosphazene compounds substituted,by both cyanophenoxy and phenoxy groups include monocyanophenoxypentaphenoxycyclotriphosphazene, dicyanophenoxytetraphenoxycyclotriphosphazene, tricyanophenoxytriphenoxycyclotriphosphazene, tetracyanophenoxydiphenoxycyclotriphosphazene, pentacyanophenoxymonophenoxycyclotriphosphazene and like cyclotriphosphazene compounds; monocyanophenoxyheptaphenoxycyclotetraphosphazene, dicyanophenoxyhexaphenoxycyclotetraphosphazene, tricyanophenoxypentaphenoxycyclotetraphosphazene, tetracyanophenoxytetraphenoxycyclotetraphosphazene, pentacyanophenoxytriphenoxycyclotetraphosphazene, hexacyanophenoxydiphenoxycyclotetraphosphazene, heptacyanophenoxymonophenoxycyclotetraphosphazene and like cyclotetraphosphazene compounds; and cyclopentaphosphazene compounds substituted by both cyanophenoxy and phenoxy groups.
Examples of the straight-chain phosphazene compounds include those substituted by both cyanophenoxy and phenoxy groups.
These phosphazene compounds may be used singly or in combination.
Among the above phosphazene compounds, phosphazene oligomers (mixtures of cyclic and straight-chain phosphazene oligomers) substituted by both cyanophenoxy and phenoxy groups are preferred in view of their production processes and availability. Particularly preferred are phosphazene oligomers wherein the ratio of cyanophenoxy group content to the phenoxy group content is 1:7 to 7:1.
The cyanophenoxy group-containing phosphazene compound (a phosphazene compound represented by the formula (3) or (4)) of the present invention can be produced by various processes.
Usable starting materials for the production of the cyanophenoxy group-containing phosphazene compound include hexachlorocyclotriphosphazene, octachlorocyclotetraphosphazene and like cyclic or straight-chain phosphazene compounds obtained by, for example, reacting ammonium chloride and phosphorus pentachloride at 120 to 130xc2x0 C., as illustrated by the following Reaction Scheme-1. Solvents usable in this reaction include tetrachloroethane, chlorobenzene and the like. 
wherein n is as defined above.
Also usable as starting materials are straight-chain dichlorophosphazenes obtained by isolating hexachlorocyclotriphosphazene from the mixture of cyclic and straight-chain phosphazene compounds prepared by the process shown by Reaction Scheme-1, heating the hexachlorocyclotriphosphazene at 220 to 250xc2x0 C. for ring-opening polymerization (see Reaction Scheme-2). 
wherein n is as defined above.
The cyanophenoxy group-containing phosphazene compound of the invention can be produced by, for example, a process comprising reacting the cyclic or straight-chain phosphazene compound obtained above, with a mixture consisting of, in a desired ratio, an alkali metal salt of a cyanophenol and an alkali metal salt of at least one member selected from the group consisting of phenols (including phenols substituted on the aromatic ring by an alkyl group having 1 to 10 carbon atoms, allyl group or phenyl group), naphthols (including naphthols substituted on the aromatic ring by an alkyl group having 1 to 10 carbon atoms, allyl group or phenyl group) and alcohols having 1 to 18 carbon atoms (these will hereinafter be referred to as xe2x80x9cphenolic compoundxe2x80x9d).
For example, a mixture of a cyanophenol, a phenolic compound and sodium hydroxide in a desired ratio is subjected to dehydration reaction to prepare sodium salt of the cyanophenol and sodium salt of the phenolic compound. This dehydration reaction is performed merely for removing water, and can be carried out with or without use of a solvent. The solvent, when used, may be benzene, toluene, xylene, chlorobenzene or the like. Azeotropic distillation using such a solvent may increase the dehydration efficiency in some cases. Subsequently, the cyclic or straight-chain phosphazene compound obtained above is added to the mixture of sodium salt of the cyanophenol and sodium salt of the phenolic compound, and the resulting mixture is subjected to substitution reaction by heating at 50 to 150xc2x0 C. for 1 to 24 hours, giving the desired cyanophenoxy group-containing phosphazene compound. 
wherein n is as defined above, and n=a+b+c.
The desired cyanophenoxy group-containing phosphazene compound can be obtained by dehydration reaction and substitution reaction, as described above. From the viewpoint of efficiency of these reactions, chlorobenzene is selected as the solvent. When chlorobenzene is used as the solvent, the substitution reaction is completed by performing the reaction at the reflux temperature of chlorobenzene for about 12 hours.
Other production processes can be also employed which include a process comprising reacting an isolated and purified cyclic or straight-chain dichlorophosphazene with the alkali metal salt of a cyanophenol and the alkali metal salt of the phenolic compound; or a process comprising reacting the dichlorophosphazene oligomer consecutively with the alkali metal salt of a cyanophenol and the alkali metal salt of the phenolic compound.
The cyanophenoxy-containing phosphazene compound obtained above is isolated and purified from the reaction mixture by a conventional isolation method such as washing, filtration, drying or the like.
Flame-retardant Resin Composition
The flame-retardant resin composition of the present invention comprises a thermoplastic resin or a thermosetting resin, and flame retardant A, B or C. Hereinafter, the term xe2x80x9cflame-retardant resin composition of the present inventionxe2x80x9d collectively refers to the resin compositions containing a thermoplastic resin or a thermosetting resin as a matrix, unless otherwise indicated.
(a) Thermoplastic Resin
A wide variety of resins known in the art may be used as the thermoplastic resin for use in the present invention. Such resins are, for example, polyethylene, polypropylene, polyisoprene, polyesters (polyethylene terephthalate, polybutylene terephthalate, etc.), polybutadiene, styrene resin, impact-resistant polystyrene, acrylonitrile-styrene resin (AS resin), acrylonitrile-butadiene-styrene resin (ABS resin), methyl methacrylate-butadiene-styrene resin (MBS resin), methyl methacrylate-acrylonitrile-butadiene-styrene resin (MABS resin), acrylonitrile-acrylic rubber-styrene resin (AAS resin), polymethyl (meth)acrylate, polycarbonate, modified polyphenylene ether (PPE), polyamide, polyphenylene sulfide, polyimide, polyether ether ketone, polysulfone, polyarylate, polyether ketone, polyether nitrile, polythioether sulfone, polyether sulfone, polybenzimidazol, polycarbodiimide, polyamideimide, polyetherimide, liquid crystalline polymer, composite plastics and the like.
Among these thermoplastic resins, polyester, ABS resin, polycarbonate, modified polyphenylene ether, polyamide, etc., are preferably used.
In the present invention, the thermoplastic resins may be used singly or in combination.
(b) Thermosetting Resin
A wide variety of resins known in the art may be used as the thermosetting resin for use in the present invention. Such thermosetting resins include polyurethane, phenol resin, melamine resin, urea resin, unsaturated polyester resin, diallyl phthalate resin, silicon resin and epoxy resin.
Among these thermosetting resins, particularly preferable are polyurethane, phenolic resin, melamine resin, epoxy resin, etc.
The epoxy resins are not limited to any specific types and may be selected from a wide variety of epoxy resins known in the art. Examples of such epoxy resins include bisphenol-A type epoxy resin, bisphenol-F type epoxy resin, bisphenol-AD type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, cycloaliphatic epoxy resin, glycidyl ester-based resin, glycidyl amine-based epoxy resin, heterocyclic epoxy resin, urethane modified epoxy resin and brominated bisphenol-A type epoxy resin.
In the present invention, the thermosetting resins may be used singly or in combination.
The amount of the flame retardant A, flame retardant B or flame retardant C relative to the thermoplastic resin or thermosetting resin is not particularly limited, but is 0.1-100 wt. parts, preferably 1-50 wt. parts, more preferably 5-30 wt. parts, based on 100 wt. parts of the thermoplastic resin or thermosetting resin.
(c) Inorganic Filler
The flame-retardant resin composition of the present invention may contain inorganic fillers to further enhance dripping preventing effect.
Conventionally, these inorganic fillers have been used mainly as reinforcements for improving the mechanical properties of resins. However, the inventors of the present invention have found that said flame retardants and inorganic fillers, when both were present in a resin, act synergistically and therefore are effective for improving the flame-retardant effects of the flame retardant, especially dripping preventive effect, as well as the mechanical properties of the resin.
When said flame retardant and the inorganic filler are both present in a resin, the surface layer of the resin becomes dense and reinforced. This prevents the diffusion of gases formed during combustion, and induces the formation of a char layer from the flame retardant, resulting in high flame-retardancy. In particular, it is essential to use the flame retardant B in combination with inorganic fillers.
The inorganic fillers may be known fillers for resins. Examples of such fillers include mica, kaolin, talc, silica, clay, barium sulfate, barium carbonate, calcium carbonate, calcium sulfate, calcium silicate, titanium oxide, glass beads, glass balloons, glass flakes, glass fibers, fibrous alkali metal titanates (potassium titanate fibers, etc.), fibrous transition metal borates (aluminum borate fibers, etc.), fibrous alkaline earth metal borates (magnesium borate fibers, etc.), zinc oxide whisker, titanium oxide whisker, magnesium oxide whisker, gypsum whisker, aluminum silicate (mineralogical name: mullite) whisker, calcium silicate (mineralogical name: wollastonite) whisker, silicon carbide whisker, titanium carbide whisker, silicon nitride whisker, titanium nitride whisker, carbon fibers, alumina fibers, alumina-silica fibers, zirconia fibers, quartz fibers and the like.
Among these inorganic fillers, it is preferred to use fillers having shape anisotropy such as fibrous fillers, e.g., fibrous alkali metal titanates, fibrous transition metal borates, fibrous alkaline earth metal borates, zinc oxide whisker, titanium oxide whisker, magnesium oxide whisker, aluminum silicate whisker, calcium silicate whisker, silicon carbide whisker, titanium carbide whisker, silicon nitride whisker, titanium nitride whisker, and mica. More preferable are fibrous alkali metal titanates, fibrous transition metal borates, fibrous alkaline earth metal borates, titanium oxide whisker, calcium silicate whisker and the like.
These inorganic fillers may be used singly or in combination.
Among these inorganic fillers, those having shape anisotropy such as whiskers and mica are preferably used.
Examples of the potassium titanate fibers among inorganic fillers include potassium hexatitanate fibers having an average fiber diameter of about 0.05-2 xcexcm and an average fiber length of about 1-500 xcexcm, and preferably having an aspect ratio (fiber length/fiber diameter) of 10 or greater. Among them, potassium hexatitanate fibers having a pH ranging from 6 to 8.5 are more preferable. A pH of potassium titanate fibers mentioned herein refers to a pH, as determined at 20xc2x0 C., of 1.0 wt. % of an aqueous suspension of potassium titanate fibers (in deionized water) which was stirred for 10 minutes. If the pH of the potassium titanate fibers is much higher than 8.5, physical properties of the resin and resistance to discoloration with heat may be disadvantageously decreased. On the other hand, when the pH is far below 6, the strength of the resulting resin composition is not effectively increased, and the residual acid may corrode processing machines and metallic molds. Hence it is not favorable.
The amount of the inorganic filler relative to the thermoplastic resin or thermosetting resin is not particularly limited. In view of a balance of improvements in mechanical properties and flame retardancy, however, the amount is 0.01-50 wt. parts, preferably 1-20 wt. parts, based on 100 wt. parts of the thermoplastic resin or thermosetting resin.
(d) Organic Phosphorus Compound Free of Halogen
The flame-retardant resin composition of the present invention may contain an organic phosphorus compound free of halogen (hereinafter referred to as xe2x80x9chalogen-free organic phosphorus compoundsxe2x80x9d) to further improve the flame retardancy thereof.
It is known that halogen-free organic phosphorus compounds are capable of improving the flame retardancy of the matrix such as resins. However, the inventors of the present invention found that when the specific phosphazene compounds for use in the present invention is used in combination with the halogen-free organic phosphorus compound, the flame-retardant effect is significantly increased due to synergism. The reason for this remarkable effect still remains to be elucidated. However, it is presumably because the conjoint use of these two compounds serves to form an expansion layer along with a char layer on the surface of the resin composition during combustion, and these layers suppress the diffusion of decomposition products and heat transfer.
A wide variety of halogen-free organic phosphorus compounds known in the art may be used in the present invention. For example, useful compounds include those disclosed in Japanese Examined Patent Publication No. 19003/1994, Japanese Unexamined Patent Publication No. 115262/1990, Japanese Unexamined Patent Publication No. 1079/1993, Japanese Unexamined Patent Publication No. 322277/1994, the specification of U.S. Pat. No. 5,122,556, etc.
Specific examples of the halogen-free phosphorus compound include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylyl phosphate, cresyl diphenyl phosphate, xylyl diphenyl phosphate, tolyl dixylyl phosphate, tris(nonylphenyl) phosphate, (2-ethylhexyl)diphenyl phosphate and like phosphates; resorcinol diphenyl phosphate, hydroquinone diphenyl phosphate and like hydroxyl-containing phosphates; resorcinol bis(diphenyl phosphate), hydroquinone bis(diphenyl phosphate), bisphenol-A bis(diphenyl phosphate), bisphenol-S bis(diphenyl phosphate), resorcinol bis(dixylyl phosphate), hydroquinone bis(dixylyl phosphate), bisphenol-A bis(ditolyl phosphate), biphenol-A bis(dixylyl phosphate), bisphenol-S bis(dixylyl phosphate) and like condensed phosphate compounds; and trilauryl phosphine, triphenyl phosphine, tritolyl phosphine, triphenyl phosphine oxide, tritolyl phosphine oxide and like phosphines or phosphine oxide compounds.
Among these halogen-free organic phosphorus compounds, preferable are triphenyl phosphate, tricresyl phosphate, trixylyl phosphate, resorcinol bis(diphenyl phosphate), hydroquinone bis(diphenyl phosphate), bisphenol-A bis(diphenyl phosphate), resorcinol bis(dixylyl phosphate), hydroquinone bis(dixylyl phosphate), bisphenol-A bis(ditolyl phosphate) and like condensed phosphate compounds; and triphenyl phosphine oxide, tritolyl phosphine oxide and like phosphine oxide compounds. In particular, preferable are the compounds such as triphenyl phosphate, resorcinol bis(diphenyl phosphate), resorcinol bis(dixylyl phosphate), triphenyl phosphine oxide and the like.
These halogen-free organic phosphorus compounds may be used singly or in combination.
These halogen-free organic phosphorus compounds are more effective when used in combination with flame retardant A or flame retardant B.
The amount of the halogen-free organic phosphorus compound relative to the thermoplastic resin or thermosetting resin is not particularly limited. In view of a balance of improvements in mechanical properties and flame retardancy, however, the amount of the halogen-free organic phosphorus compound is 0.1-50 wt. parts, preferably 1-30 wt. parts, based on 100 wt. parts of the thermoplastic resin or thermosetting resin. The amount of the flame retardant to be added thereto is 0.1-50 wt. parts, preferably 5-30 wt. parts, based on 100 wt. parts of the thermoplastic resin or thermosetting resin.
(e) Fluorine-containing Resin
Further, a fluorine-containing resin may be incorporated into the flame-retardant resin composition of the present invention containing a thermoplastic resin as a matrix within the range which does not adversely affect the object of the present invention. The amount of the fluorine-containing resin to be used is not particularly limited, but is 0.01-2.5 wt. parts, preferably 0.1-1.2 wt. parts, based on 100 wt. parts of the thermoplastic resins.
A wide variety of fluorine-containing resins known in the art may be used in the present invention. The examples include polytetrafluoroethylene resin (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA), tetrafluoroethylene-ethylene copolymer resin (ETFE), polychlorotrifluoroethylene resin (CTFE) and polyvinylidene fluoride (PVdF). Among these, PTFE is particularly preferable. By the addition of the fluorine-containing resins, the dripping preventing effect is produced in a more pronounced manner.
Fluorine-containing resins are more effective when used in combination with flame retardant A.
(f) Other Additives
The flame-retardant composition of the invention is a resin composition which does not contain a halogen (e.g., chlorine, bromine)-containing compound as a flame retardant component but can produce excellent flame retardant effects. One or more flame retardant additives conventionally used may be incorporated into the composition insofar as they do not adversely affect the excellent effects.
The flame retardant additive for use is not limited, and usually any additive that produces flame retardant effects can be used. Examples of useful flame retardant additives are metal oxides such as zinc oxide, tin oxide, iron oxide, molybdenum oxide, copper oxide and manganese dioxide; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, oxalic acid-treated aluminum hydroxide and nickel compound-treated magnesium hydroxide; alkali metal salts or alkaline earth metal salts such as sodium carbonate, calcium carbonate, barium carbonate and sodium alkylsulfonate; organic chlorine compounds or organic bromine compounds such as chlorinated paraffin, perchlorocyclopentadecane, tetrabromobisphenol-A; epoxy resins, bis(tribromophenoxy)ethane and bis(tetrabromophthalimino)ethane; antimony compounds such as antimony trioxide, antimony tetraoxide, antimony pentaoxide and sodium antimonate; red phosphorus, halogen-containing phosphoric ester compounds, halogen-containing condensed phosphoric ester compounds or phosphonic acid ester compounds, nitrogen-containing compounds such as melamine, melamine cyanurate, melamine phosphate, melam, melem, mellon, succinoguanamine, guanidine sulfamate, ammoninum sulfate, ammonium phosphate, ammonium polyphosphate and alkylamine phosphate; boron compounds such as zinc borate, barium methaborate and ammonium borate; silicon compounds such as silicone polymers and silica; and thermally expansive graphite.
These flame retardant additives can be used singly or in combination.
Incorporating a trace amount of a Lewis acid into flame-retardant resin compositions containing flame retardant C of the invention imparts further improved heat resistance and flame retardancy to the resin. Useful Lewis acids include a wide variety of those known, for example, zinc chloride, ferric chloride and the like. These Lewis acids can be used singly or in combination, and the amount of the Lewis acid to be incorporated is usually about 0.01 to about 0.6 wt. parts, based on the total weight of the flame-retardant resin composition.
Further, one or more conventional resin additives may be incorporated into the flame-retardant composition of the invention, insofar as they do not adversely affect the excellent properties. Examples of useful resin additives include flame retardants other than the aforementioned ones, dripping inhibitors (dropping inhibitors), UV absorbers, light stabilizers, antioxidants, light screens, metal deactivators, quenching agents, heat resistance stabilizers, lubricants, mold releasing agents, coloring agents, antistatic agents, antiaging agents, plasticizers, impact strength improving agents and compatibilizers.
The UV absorber is a component for absorbing light energy and releasing the absorbed light energy harmlessly in the form of heat energy by the transformation thereof into a keto form through intramolecular proton transfer (in the case of benzophenones and benzotriazoles) or by cis-trans isomerization (in the case of cyanoacrylates). Specific examples of UV absorbers include 2-hydroxybenzophenones such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone and 5,5xe2x80x2-methylenebis(2-hydroxy-4-methoxybenzophenone); 2-(2xe2x80x2-hydroxyphenyl)benzotriazoles such as 2-(2xe2x80x2-hydroxy-5xe2x80x2-methylphenyl)benzotriazole, 2-(2xe2x80x2-hydroxy-5xe2x80x2-t-octylphenyl)benzotriazole, 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-di-t-butylphenyl)benzotriazole, 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2xe2x80x2-hydroxy-3xe2x80x2-t-5xe2x80x2-methylphenyl)-5-chlorobenzotriazole, 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-dicumylphenyl)benzotriazole and 2,2xe2x80x2-(methylenebis(4-t-octyl-6-benzotriazolyl)phenol; benzoates such as phenylsalicylate, resorcinol monobenzoate, 2,4-di-t-butylphenyl-3xe2x80x2,5xe2x80x2-di-t-butyl-4xe2x80x2-hydroxybenzoate and hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate; and substituted oxalic anilide such as 2-ethyl-2xe2x80x2-ethoxy oxalic anilide and 2-ethoxy-4xe2x80x2-dodecyl oxalic anilide; cyanoacrylates such as ethyl-xcex1-cyano-xcex2,xcex2-diphenylacrylate and methyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate.
The light stabilizer is a component for decomposing hydroperoxides produced by light energy into stable N-O.radical, Nxe2x80x94OR or Nxe2x80x94OH, thereby providing light stability. For example, hindered amine light stabilizers can be used. Specific examples of light stabilizers include 2,2,6,6-tetramethyl-4-piperidyl-stearate, 1,2,2,6,6-pentamethyl-4-piperidylstearate, 2,2,6,6-tetramethyl-4-piperidylbenzoate, bis(2,2,6,6-tetramethyl-4-piperidylsebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-sebacate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane tetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-di(tridecyl)-1,2,3,4-butanetetra-carboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-butyl-2-(3xe2x80x2,5xe2x80x2-di-t-butyl-4-hydroxybenzyl)malonate, 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-piperidinol/diethyl succinate polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane/dibromoethane polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane/2,4-dichloro-6-t-octylamino-s-triazine polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane/2,4-dichloro-6-morpholino-s-triazine polycondensate, and the like.
The antioxidant is a component for stabilizing peroxide radicals, such as hydroperoxy radicals, which are formed upon heat with molding or light exposure, or for decomposing generated peroxides, such as hydroperoxides. Examples of antioxidants include hindered phenol type antioxidants and peroxide decomposers. The hindered phenol type antioxidant acts as a radical chain-transfer inhibitor, and the peroxide decomposer decomposes peroxides generated in the reaction system into a stable alcohol, and prevents autoxidation.
Specific examples of hindered phenol type antioxidants include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3-(3,5-di-t-butyl-4-hydroxylphenyl)propionate, 2,2xe2x80x2-methylene bis(4-methyl-6-t-butylphenol), 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate, 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenylacrylate, 4,4xe2x80x2-butylidene bis(3-methyl-6-t-butylphenol), 4,4xe2x80x2-thiobis(3-methyl-6-t-butylphenol), alkylated bisphenol, tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)proprionate]methane, 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, and the like.
Examples of peroxide decomposers include organic phosphorus type peroxide decomposers such as tris(nonylphenyl)phosphite, triphenyl phosphate and tris(2,4-di-t-butylphenyl)phosphite; and organic thio type peroxide decomposers such as dilauryl-3,3xe2x80x2-thiodipropionate, dimyristyl-3,3xe2x80x2-thiodipropionate, distearyl-3,3xe2x80x2-thiodipropionate, pentaerythrityltetrakis(3-laurylthiopropionate), ditridecyl-3,3xe2x80x2-thiodipropionate and 2-mercaptobenzimidazole.
The light screen is a component for preventing light from penetrating into the bulk of a polymer. Specific examples of light screens include titanium oxide having a rutile structure (TiO2), zinc oxide (ZnO), chromium oxide (Cr2O3) and cerium oxide (CeO2).
The metal deactivator is a component for deactivating heavy metal ions in the resin by forming a chelate compound. Specific examples of metal deactivators include benzotriazoles and derivatives thereof (e.g. 1-hydroxybenzotriazole and the like).
The quenching agent is a component for deactivating photo-excited hydroperoxides and functional groups such as carbonyl groups in the polymer due to energy transfer. Useful quenching agents include organic nickel and the like.
In order to impart improved antifogging, antifungal, antimicrobial or like properties, other conventionally known additives may also be added.
Production of Flame-Retardant Resin Compositions of the Invention
The flame-retardant resin composition of the invention can be produced by mixing a thermoplastic resin or a thermosetting resin and the aforementioned frame retardant, optionally toghether with an inorganic filler, a halogen-free organic phosphorus compound, a fluorine-containing resin, one or more flame retardant additives and other additives, in prescribed or proper amounts, followed by mixing and kneading the mixture by a conventional method. For example, the mixture of components in the form of powder, beads, flakes or pellets is kneaded using an extruder, e.g., a uniaxial extruder or a biaxial extruder, or a kneader, e.g., Banbury mixer, a pressure kneader or a two-roll mill, giving a resin composition of the invention. When a liquid needs to be added, a conventional liquid injection device can be used and the mixture can be kneaded using the aforementioned extruder, kneader or the like.
Flame-Retardant Resin Moldings of the Invention
The flame-retardant resin composition of the invention can be molded into flame-retardant resin moldings. For example, the resin composition can be molded into resin plates, sheets, films, special shapes or like extrusion moldings of various shapes using a conventional molding method such as press molding, injection molding or extrusion molding, or can be molded into a resin plate of two- or three-layered structure using a coextruder.
The thus-obtained flame-retardant resin composition and flame-retardant resin moldings of the invention can find wide application in various industrial fields, such as electrical, electronics or telecommunication industries, agriculture, forestry, fishery, mining, construction, foods, fibers, clothing, medical services, coal, petroleum, rubber, leather, automobiles, precision machinery, timber, furniture, printing, musical instruments, and the like.
Stated more specifically, the flame-retardant resin composition and flame-retardant resin moldings of the invention can be used for business or office automation equipment, such as printers, personal computers, word processors, keyboards, PDA (personal digital assistants), telephones, facsimile machines, copying machines, ECR (electronic cash registers), desk-top electronic calculators, electronic databooks, electronic dictinaries, cards, holders and stationery; electrical household appliances and electrical equipment such as washing machines, refrigerators, cleaners, microwave ovens, lighting equipment, game machines, irons and kotatsu (low, covered table with a heat source underneath); audio-visual equipment such as TV, VTR, video cameras, radio cassette recorders, tape recorders, mini discs, CD players, speakers and liquid crystal displays; and electric or electronic parts and telecommunication equipment, such as connectors, relays, condensers, switches, printed circuit boards, coil bobbins, semiconductor sealing materials, electric wires, cables, transformers, deflecting yokes, distribution boards, and clocks and watches.
Further, the flame-retardant resin composition and flame-retardant resin moldings can be widely used for the following applications: materials for automobiles, vehicles, ships, aircrafts and constructions, such as seats (e.g., padding, outer materials), belts, ceiling covering, convertible tops, arm rests, door trims, rear package trays, carpets, mats, sun visors, wheel covers, mattress covers, air bags, insulation materials, hangers, hand straps, electric wire coating materials, electrical insulating materials, paints, coating materials, overlaying materials, floor materials, corner walls, deck panels, covers, plywoods, ceiling boards, partition plates, side walls, carpets, wall papers, wall covering materials, exterior decorating materials, interior decorating materials, roofing materials, sound insulating panels, thermal insulation panels and window materials; and living necessities and sporting goods such as clothing, curtains, sheets, plywoods, laminated fiber boards, carpets, entrance mats, seats, buckets, hoses, containers, glasses, bags, cases, goggles, skies, rackets, tents and musical instruments.
The present invention will be specifically described below with reference to Synthesis examples, Examples and Comparative Examples. In the following description, parts and % mean weight parts and weight %, respectively, unless otherwise specified. In addition, Phxe2x80x94 means phenyl group and xe2x80x94Phxe2x80x94 means phenylene group.
Phenol (2.04 moles, 196 g) and 2.04 moles (82 g) of sodium hydroxide were subjected to azeotropic dehydration with use of toluene to prepare about 1200 g of a 20% solution of sodium phenolate in toluene.
In parallel with the above reaction, 580 g of a 20% solution containing 115.9 g of dichlorophosphazene oligomers (a mixture of 58.57% of trimer, 12.26% of tetramer, 11.11% of pentamer and hexamer, 2.82% of heptamer, 12.04% of octamer and higher oligomers) in chlorobenzene was placed in a 4-necked, 2-liter flask, and a 10% solution containing 0.15 mole (18.3 g) of separately prepared hydroquinone dilithium salt in toluene was added dropwise thereto with stirring. After the dropwise addition, the mixture was subjected to a reaction with stirring at 50xc2x0 C. for 5 hours. Subsequently, about 1200 g of the previously prepared 20% solution of sodium phenolate in toluene was added dropwise thereto, and the resulting mixture was subjected to a reaction with stirring at 100xc2x0 C. for 8 hours.
After the reaction was completed, the reaction mixture was concentrated and poured into 3 liters of a mixture of water/methanol (1/1 by volume) with stirring, and the mixture was neutralized with dilute sulfuric acid and filtered. The obtained product was washed twice with 3 liters of a mixture of water/methanol (1/1 by volume), separated by filtration, and dried in a vacuum with heating at 80xc2x0 C. at a pressure of 20 mmHg for 11 hours to give 220 g of a pale yellow powder.
The crosslinked phenoxyphosphazene compound obtained above did not show a definite melting point, and showed a decomposition starting temperature of 305xc2x0 C. as determined by TG/DTA analysis. It was found from the phosphorus content and CHN elemental analysis data that approximate composition of this crosslinked phenoxyphosphazene compound was [Nxe2x95x90P(xe2x80x94Oxe2x80x94pxe2x80x94Phxe2x80x94Oxe2x80x94)0.15(xe2x80x94Oxe2x80x94Ph)1.7].
A 86.7 g-quantity of bisphenol-A (0.38 mole) and 460 ml of tetrahydrofuran (THF) were placed in a 4-necked, 2-liter flask, and while maintaining the internal temperature at 19xc2x0 C., 3.5 g (0.5 mole) of Li metal in the form of cut pieces was added thereto with stirring. After the completion of the addition, the temperature was elevated to 61xc2x0 C. over 1 hour, and the stirring was continued for 4 hours at 61xc2x0 C. to 68xc2x0 C. After the reaction was completed, the resulting reaction mixture containing lithium salt of bisphenol-A became a white slurry form.
A 215.6 g-quantity of phenol (2.25 moles) and 500 ml of toluene were placed in a 4-necked, 3-liter flask, and while maintaining the internal temperature at 25xc2x0 C., 34.5 g (1.5 moles) of sodium metal in the form of cut pieces was added thereto with stirring. After completion of the addition, the temperature was elevated to 77xc2x0 C. over 4 hours, and the stirring was continued for 3 hours at 77xc2x0 C. to 113xc2x0 C. After the reaction was completed, the reaction mixture containing sodium phenolate became a white slurry form.
A 313.13 g (1.0 mole) quantity of dichlorophosphazene oligomers (concentration 37.01%, monochlorobenzene solution, a mixture of 58.57% of trimer, 12.26% of tetramer, 11.11% of pentamer and hexamer, 2.82% of heptamer, 12.04% of octamer and higher oligomers) was placed in a 4-necked, 5-liter flask, and while maintaining the internal temperature at 20xc2x0 C., the solution of lithium salt of bisphenol-A was added dropwise thereto over 1 hour with stirring, whereby the content became a pale yellow milk form. Then, while maintaining the internal temperature at 20xc2x0 C., the sodium phenolate solution was added dropwise thereto over 1 hour with strring, whereby the content became a brown slurry form. After the dropwise addition, the stirring was continued for 13 hours at 47xc2x0 C., whereby the content became a pale brown slurry form.
After the reaction was completed, the reaction mixture was concentrated, and the concentrate was washed three times with 3 liters of a 2% NaOH, filtered, washed three times with 3 liters of a mixture of water/methanol (1/1 by volume), filtered, and subjected to a vacuum drying with heating at 80xc2x0 C. at 20 mmHg for 11 hours to give a white powder.
Yield: 208.67 g
Yield based on dichlorophosphazene: 86.50%
The obtained compound had a hydrolyzable chlorine content of 0.93%, a decomposition temperature of 296.0xc2x0 C., and a 5% weight loss temperature of 307.7xc2x0 C. It was found from the phosphorus content and CHN elemental analysis data that the composition of the final product was [Nxe2x95x90P(xe2x80x94Oxe2x80x94Phxe2x80x94C(CH3)2xe2x80x94Phxe2x80x94Oxe2x80x94)0.25(xe2x80x94Oxe2x80x94Ph)1.50].
Following the procedure of Synthesis Example 1 and using resorcinol in place of hydroquinone, reaction and workup were carried out, thereby giving a product represented by the formula [Nxe2x95x90P(xe2x80x94Oxe2x80x94mxe2x80x94Phxe2x80x94Oxe2x80x94)0.15(xe2x80x94Oxe2x80x94Ph)1.7] as a white powder. This crosslinked phenoxyphosphazene compound did not show a definite melting point, and showed a decomposition starting temperature of 300xc2x0 C. as determined by TG/DTA analysis.